Improved pantographic telegraph



UNITED STATES PATENT OFFICE0 GIOVANNI OASELLI, OF FLORENCE, ITALY.

IlVl PROVED PANTOGRAPHIC TELEGRAPH.

Specification forming part of Letters Patent No. 20,695, dated June 29,1858.

To all whom it may concern:

Be it known that I, GIOVANNI GAsELLI, of Florence, in the Kingdom ofItaly, have invented new and useful Improvements in Electric Telegraphs,which improved telegraph I call the Iantographic Telegraph, of which thefollowing is a specification.

The nature ot' my invention consists in the production and transmissionwith the greatest possible rapidity of facsimiles of writings anddrawings by sending and receiving at the saine time several dispatchesby a single wire, and without effecting any change in the arrangementot' the telegraphic lines already in existence.

As one ot' the chief` advantages of my telegraph lies in the rapiditywith which dispatches can be received and transmitted, I hasten to statethat this rapidity can be increased, as we shall see later, in the ratioof the dimensions which it is proposed to give to the telegraphicmachines.

The following is a full description, reference being had to theaccompanying drawings.

A B O l), a cast-iron stand ot' a pyramidal form, supports a metallicpendulum, a b c d, of the length of one hundred and forty centimeters.It is suspended by a horizontal axis, ot' which the two extremities arecylindrical, and which restson four wheels of equal diameter. Figure IIIrepresents the cast-iron stand, seen laterally.

At the lower extremity of the pendulum there is fixed at right angles anelectro-magnet, d', having the form of a rectangular parallelopiped, asis morevclearly seen in Fig. IV, as well as in Fig. V, representing thesame pendulum where viewed laterally.

Two pieces, c c', thoroughly welded, are of forged iron, destined toserve as armature on the electro-magnet d. They are solidly fixed on thesides of the base ofthe stand A B C D, as is also seen in Fig. VIII,representing the plan of the machine.

Fig. VII represents an electro-magnetic apparatus, which I shall terminterrupter of the line,77 and ot" which we shall presently see theaction.

B is a voltaic pile ot' Bunsen, of whichthe circuit is formed by acopperwire. (Represented in the drawings by a dotted line.)

far as the point s, to which itis joined by a spiral wire, and afterhaving traversed the mercury which is in the basin u', arrives at thescrew-button No. 4 and returns to Bunsens pile B. The electric currentof this pile having thus magnetized the piece of iron d', which is atthe extremity of the pendulum, the latter is retained by the armature c,but it is unable to touchit, from its being covered with alayer ofcaoutchouc.

In order to interrupt the current of the pile B', which I shall call thelocal pile,77 there is employed (as we shall see) the current of thetelegraphic line, proceeding from the battery D. Before examining thedirection taken by the current of this battery, let us tix fora momentour attention on the other pieces of the telegraphic machine.

A stand of cast-iron, L L, supports two parallel cylinders, one,ff, isvisible in the ,Iirst gure, and the position of the other,j"f, may beobserved in Fig. VIII, which represents the ground plan ofthe machine. Ahorizontal metallic rod, o o, bent at right angles at c and if, andjointed at the point c', must in consequence follow the movements of thependulum. It is supported by the vertical rod s a, in such a way thatits extremity x traverses a straight horizontal line, while the pendulumoscillates and the point o describes the arcs ot' a circle. The otherrod, o o', also traverses with its eX- tremity a horizontal line. Now,if we sup pose that the current of the electro-telegraphic battery Dleaves the pole l we shall see that it arrives by means of the copperwire (repreA sented in the drawings by red lines at the knob or buttonNo. 2 of the machine, Fig. l) and reaches the point a, where the saidwire branches oft in lines. The one of these two branches which descendsas far as the cylinder f f, which is isolated, can afford no passage tothe current, which by the other branch will In proceeding to examine thedirection to be conducted to the point2 at the cup a, filled withmercury. The electric current will pass from the mercury to a platinapoint attached to the spring m, which is pressed on by the smallcylinder z, fixed on the lever u z. This current then traversing themechanical interrupter t, it will come to the knob or button No. 8, andwill arrive at the interrupter of the line, Fig. VII. Thence, afterhaving passed along the electro-magnetic reels p', the same current willreturn to the machine by the knob or button No. 9, and it will touch thepoint u, where the metallic communication is again divided into twobranches. That formed by the lever u s, having, as we shall presentlysee, no continuity, cannot afford a passage to the electricity 5 but theother branch conducts the current by the knob or button No. 1 to thewire by which the two stations are placed in communication.

As the instruments of the two stations are exactly equal in theirconstruction, it follows that the current of the line arrives at theknob or button No. l, second ligure. It takes, in a contrary sense, inthis second machine the same direction that it has taken in the other.It reaches a copper plate, p Z, which is plunged in a well, and returnsby the earth to the battery D', Fig. I. This constant traversing of theelectric current is accomplished in a fraction of time quiteindistinguishable, whatever be the distance existing between the twostations. It is thus that when the pieces of the instrument will havethe positions represented in the drawings the current of the line musttraverse at the same time the reels ot the interrupter of the line, Fig.VII, and of' the one corresponding to it at the other station. Thetemporary magnetism produced by these reels in the iron cylinder, bywhich they are traversed, exerts its force at both stations on thelevers w. The currents of the local piles B being thus interrupted, atthe same time the pendulums will no longer be detained by theelectro-magnets d', and both are set in motion to accomplish theiroscillations in obedience to the terrestrial attraction. When themovement of the pendulums has commenced the platina points being nolonger pressed down in the cups 'w y by the small cylinder z and by thesmall hammer u, (which follows the movement of the lever u s, in whichthey are tixed,) separated from the mercury, and thus at this part alsothe metallic communications of the piles B' D remain broken. As the small cylinder z' on arriving presses the spring m an instant before theoscillation of the pendulums has been completed, it closes again thecircuit of the local pile B', and the electromagnet d' is attractedtoward its armature e', from which it cannot be detached until thelittle hammers n have unclosed the circuit of the telegraphic line. Thenthe parallelopipedon of iron d', Figs. I and 1I, remaining both deprivedof magnetism, will fall back toward the iron armatures e and e', whichare on the other side. In this manner the oscillations of the pendulumought to be continuous and synchronous. It will be entirely understoodthat this synchronism is not dependent on the velocity, which isnaturally peculiar to the two pendulums set in motion by the terrestrialattraction, because if even one of the two should arrive from any causewhatsoever and complete its oscillation a moment before the other itought to stop attached to its ar1nature,wait ing until the otherpendulum should complete its movement to fall back with it at the sameinstant. It results from this arrangement that the local piles B', Figs.I and II, supply the force, keeping up the oscillating motions of thependulums, and that the current of the line regulates the synchronism ofmovements.

Let us now proceed to examine the functions of the current of the linewhile the pendulums drawn by their own weight are removed i'rom thearmatures e c'. They advance to the right or the left. K

We have already seen how, when the spring m is no longer pressed down bythe small cylinder z, it rose, withdrawing the platina point from themercury contained in the vase w. The current ot' the line has been thusinterrupted on this side, but at the same moment. The steel point r,which is attached to the lever p, being freed by means of the pressureot' the small cylinder m on the piece b2, has come to rest on thecylinderff, and grazes it in the direction of the oscillation otl thependulum. Meanwhile the current of the line having arrived at the buttonor knob No. 1, and afterward at the point u, traverses the rods u' s ando' o' x' until it reaches the metallic point r. From this point theelectric current passes by the cylinder ff to the copper wire y y', andhaving reached the point r r, being unable to pass by thelittle vase w,from which the platina point has been raised by means of the spring m,it continues its course to the button or knob No. 2 across the batteryD', arrives at the copper plate p Z, plunged in the Well, and, passingthrough the earth to the other station, traverses equally the batteryD', and enters by the button or knob No.2 the other telegraphicmachine,where, after having followed, in an inverse sense, the same pathalready taken in the first machine, it comes out at the button or knobNo. l and performs by the wire of the line the telegraphic circuit.

To render this description clearer we have hitherto supposed that thesteel point touched immediately the cylinderff; but now we must remarkthat on this cylinder are placed certain sheets of paper, 7c 7c, whichthe said point 2 grazes in a straight line. The paper placed on thecylinder ff, Fig. I, must be silvered over or covered over with a verytine coating of tin or zinc. On this metallized paper there has beenpreviously written, with common pen and ink, the dispatch of which afac-simile is required at the other station. On the correspondingcylinder at the other station there is placed paper chemically preparedwith cyanide of potassium. If the voltaic batteries were arranged insuch a way that the point r' belonging to the second machine wereelectried positively bythe current of theline during the oscillations ofthe pendulum, this point would produce on the chemical paper p p a lineof blue color parallel with the axis of the cylinder f j'. Theoscillation of the pendulum being continual, the point 1 ought to gobackward and forward by the same line on the chemical paper; but itisnecessary to observe that the said cylinder is in communication with aspecial mechanism, t', which imparts to it a rotating motion about itsown axis, so that at each oscillation of the pendulum the surface of thecylinder, and consequently of the paper placed on it, keeps constantlyadvancing in the direction of the arrow j', Fig. I. This mechanismconsists, chiefly, in a disk of brass, fixed by its center on thecontinuation of the axis of the cylinder. Fig. Vl represents it seenlaterally, and in front a lever, a b, grooved at i, terminates in alittle plate of iron, b i". Asecond lever, s s', grooved in thefirstath, rests with its extremity aon the periphery of the disk c1, and iskept there by the pressure of the spring m, Fig. Vl. By causing thelever a bto describe arcs around the center t in moving alternately tothe right and left its extremity b, the disk d and the cylinder to whichit is attached will acquire a rotating motion on their common axes inthe direction of the arrow s. This motion is produced in the telegraphicmachines by successive shocks inthe following manner: We have alreadyseen how at the termination of even oscillations ofthe pendulum thecircuit ofthe local pile B remains closed for a moment. While thishappens a secondarycurrent is developed in the wire t b, which, bymagnetizing the electro magnets, attracts the piece of welded iron b i',which, then, on the interruption ofthe current, is brought back to itsprimitive position by the antagonistic spring r. The same rotatingmotion of the cylinders and consequent unwinding of the paper iscontemporaneous in the two corresponding machines. Supposing, now, thatthe ink with which the dispatch has been written be an imperfectconductor of electricity, (and common black ink has, in truth, thisquality,) we can easily understand that whenever the point 1', ingrazing the metallic paper pp, happens to touch the writing the currentof thetelegraphicline will be interrupted, and, to speak more strictly,weakened, and as with every diminution ofthe force of the current theintensity ot'the color on the chemical paper placed at the other stationwill be also weakened, there will be seen on the latter a multitudeofpoints less colored, which, on a sheetof deeper ground, will be soarranged as to present the image ofthe writing or drawing intended to bereproduced. This image, however, will always be pale and with difficultydiscernible, and if the original be not written in-a very largecharacter no effect will be produced. This imperfection is owing to thefact that as these do not become immediately destroyed `by theinterruption of the current, the chemical action of the iron point o",

the colored lines are prolonged more than is necessary and tendto fillup the intervals, which, by remaining blank, ought to form thetelegraphic fac-simile.

In order to obtain a perfect specimen and true fac-simile of theoriginal characters described in colored lines on white paper it wasnecessary, rst, to give to the electrical circuits an arrangement whichthere might be obtained an effect opposed to that which we have traced,and nd a way that the chemical action of the point 2 might remaininstantaneously destroyed, not only by the interruption of the currentof the line, but by the mere weakening of the same. I succeed inprocuring this result by arranging the circuits ofthe voltaic pile inthe manner which, for greater clearness, is drawn in Fig. X. A wire, def g, connects in the usual way the poles of the voltaic battery a b. Theline 7s is a second copper wire, which, united at f with the other wire,performs the partial circuit 7c b g ofthe galvanic element a Y What willhappen in the wire k while the entire battery a b is in action? Theelectric current directed from the point g toward the opposite pole, d,is compelled, on its arrival at the point j", to divide. Part of itfollows the wire k in the direction of the dark arrow. The other partgoes from the point f to the pole d. The voltaicelement, however, a',having its own electric circuit, tends to transmit a portion of its owncurrent by the same wire ic according to the direction or" the redarrow. Thus there will be two currents in an opposite direction in thesame wire ic,- or, to speak with greater truth, there will only pass bythis wire the difference of the currents themselves. The electro-motiveforce of the sole element a is inferior to that derived from the otherelements united. The wire 7c will therefore have a surplus of current inthe direction of the black arrow, especially it' the wire 7c be ot' sucha nature as to offer a marked resistance to the passage oftheelectricity 5 but as often as the metallic circuit shall bc interruptedat g there will be an inversion ofthe current in the wire k, which willthen freely be traversed by the contrary electricity derived from theelement a'. In this way, as the circuit of the pile a will remain alwaysclosed, there can be pro'- du-ced at will an inversion of the current inthe wire ir.

XVe shall now see how, by these combinations of the electric circuit, wecan obtain from the pantographic telegraph-dispatches colored with theutmost exactness on a white ground. In Figs. I and II we see some linesofa blue color, of which we have not hitherto spoken. The copper wirerepresented by these lilies is attached to the metallic arc 00', whichis isolated, and cannot have any iniiuence in the electric operationsofthe machines, Fig. I, which we have hitherto described, but in Fig. Ilwe see that while the pendulum oscillates from left to right the smallcylinder 002, fixed to the lever c a, grazes with its metallic part andestablishes just such a system of electric communication in thetelegraph analogous with that represented in Fig. X. In fact, thecurrent of the line derived from the first machine reaches the second atthe button or knob No. directs itself toward u in the lever u s',passes, by means of the small cylinder .002, to a mctallicarc, m rm, andthence to the knob No. 3, continues its course as far as the positivepole of the pile a', (which thus becomes placed in communication withthe other pile, D', forming, along with it, a single voltaic battery,)and returns by the earth to the other station. The wire g/ is thus putin communication with the positive pole of the pile D and at the sainetime with .the negative pole ofthe pile d. It thus arrives at the knobNo. 2 of the machine, Fig. II, and the electric communication which isestablished continues by the wire 102 w' to, arrives at the cylinder ff,and at the iron point r, continues along the rods 0 s s u2 and comes tothe point u2, where it is reconnected with the circuit of the wholebattery, consisting of the piles a D. The wireQ,I `ig. I, is thus placedin the same conditions with the wire k, Fig. X, when the pendulumoscillates from left to right, and the direction of the currentbelonging to it will be immediately reversed at every interruptionoccurring in the current connecting the two stations. Now, as often asthe iron point 1" shall becolne positively electrified the color willappear in the point of the chemical paper placed beneath it 5 and as theinterruption of the current of the line and the consequent electrizationof the iron point is repeated, as we have seen, at each point of thewriting or original drawing touched by the metallic stylus r, Fig. I, itis evident that the colored point will represent on the chemical paper afacsimile of the original placed on the cylinder at thetransmitting-station.

In hitherto describing the different operations of the pantograph wehave considered only the effects derived from the oscillation of thependulums when going from left to right. Iiet'us now examine what occursin the contrary oscillationsthose from right to left.

When we attentively observe in both machines the small cylinder x2,lixed on the lever a c, we see that it, when the pendulum is in motion,will alternately graze the upper and lower surface of the arc n fn,which is formed by an elastic band of metal. In this way as the circuitofthe pile a remains successively closed and opened the telegrapicmachine Fig. II will transmit dispatches while the pendulum moves fromleft to right, and will receive them while performing the contrarymotion. The same thing in an inverse order occurs in the machine Fig. I,so that while the latter transmits the former receives dispatches, andthe reverse. In order better to understand how this happens we mustobserve the form and use of certain mechanism.

Fig. IX represents the pendulum a b c t separated from the machine withits appendages.

The cross-lever m j' is supported by means of a pivot at the pointf fromthe perpendicular lever ej", jointed in c. The length of the levers c fand c f has such proportions that while the pendulum oscillates, and, inconsequence, j" f describes arcs around the centers c c, the extremitiesx of the cross-levers take a direction nearly approaching that of astraight line, and the space which it traverses is equal to that of thechords subtending the arcs themselves, which are of equal length. Thissystem of levers in the pantograph is double, and we have x and fr',which traverse the space in a straight line. At .r and there are xedsmall levers p, having at their ends the needles that are to graze alongthe paper. Vhen the pendulum swings from left to right a small leversupported by a hasp is raised in such a way that the point does nottouch the paper placed on the cylinder; but when the oscillation hasbeen completed the same lever, freed from the hasp, falls, and by itsown weight presses on the paper with its point at the same time thelever is raised up and caught in the hasp by means of the smallcylinder. The two points act thus alternately, and their effects areproduced separately on the two cylinders ot' each machine. If a chemicalpaper be placed on the second cylinder of the instrument Fig. I, and themetallic sheet on which the dispatch is written be laid on thecorresponding cylinder of the machine Fig. II, a new telegraphiccommunication will be opened, and our machine can thus at the same timetransmit and receive several dispatches.

To complete the present description of the I pantograph it remains toprove the truth of what we said in the commencement, viz., that therapidity of the transmission of the dispatches augments in the ratio ofthe size of the telegraphie machine.

In the machine of which wehave here given the plan, the point a ofthependulum describes in a second an arc, of which the chord, equivalent tothe space traversed on the paper by the point writing, is about sixtycentimeters. Supposin g that the dimensions of the machines werequadrupled, the point writing a ought to traverse in two seconds a spaceof two hundred and forty centimeters. In this way the product of thetelegraphic machine would be quadrupled in twice the time or double inany given time. It is not necessary to add that this velocity would begreatly augmented if short-hand writing were employed in thetransmission of dispatches. y Note I. The interruption of the circuit ofvoltaic pile B is produced by the interrupter, Fig. VII, when thecurrent ofthe telegraphic line passes along the spirals on m. The leverrises and interrupts the circuits by means of the platina point t, whichcomes out of the mercury contained in little bowl y, and remainsimmersed in the alcohol, which is placed above the mercury itself. Thepoint y remains always immersed in the mercury of the other Vase, s.

Note II. This small cylinder x" is thus composed: One half of copper andthe other half iron, each having the form of a half-cylinder. Ihesurfaces of the two pieces in contact with each have the figure of arectangular plane, dividing the cylinder into two equal parts, passingthrough its axis.

Note III. To construct a telegraphic machine of any size whatever themeasure of the lever alb may be found by the following trigonometricalformula: If 2 be the length, ef: the half of the angle of theoscillation of the pendulum, ab e d u the cross-lever,f p the portion ofthe said line comprised between the jointing, j" f: w the unknown line fe', we shall have 00:00 sine 25k (1022L p)|a2 r.

In short, the advantages of my invention are rapidity of transmissionot' fac-similes of writings, drawings, or ciphers; secrecy of thecorrespondence; the transmitting different dispatches at the same timeand with a single wire; the width of the dispatches in proportion todimension of machinery; impossibility of error in transmission;continuity of work, as dispatches can be put on the cylinder withoutinterrupting the movement; regularity in the movement of the machineskept up by terrestrial attraction, and by the continuous action of thetelegraphic current.

I do not claim the general use of electricity for producing fac-similesupon chemically-prepared paper or other material; but

What l do claim as new, and desire to secure by Letters Patent, is-

1. The mode of rapidly transmitting the facsimiles of writings,drawings, ciphers, and arbitrary signs, in colored characters, uponordinary white or chemically-prepared paper, substantially as described.

2. The mode of receiving and transmitting different dispatches at thesame time and with a single wire, as described.

8. rIhe use of local piles with circuit always closed for the productionof the characters on chemically-prepared paper, as described.

Paris on the 20th July, 1857.

GIOVANNI OASELLI.

Witnesses:

GEO. HU'r'roN, JNO. WALLER.

